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1 /*
2  *
3  * Copyright 2016 gRPC authors.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *     http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  */
18 
19 #include <grpc/support/port_platform.h>
20 
21 #include <string.h>
22 
23 #include "absl/strings/str_format.h"
24 
25 #include <grpc/impl/codegen/slice.h>
26 #include <grpc/support/alloc.h>
27 #include <grpc/support/log.h>
28 #include <grpc/support/string_util.h>
29 
30 #include "src/core/lib/channel/channel_args.h"
31 #include "src/core/lib/channel/handshaker.h"
32 #include "src/core/lib/debug/trace.h"
33 #include "src/core/lib/iomgr/timer.h"
34 #include "src/core/lib/slice/slice_internal.h"
35 
36 namespace grpc_core {
37 
38 TraceFlag grpc_handshaker_trace(false, "handshaker");
39 
40 namespace {
41 
HandshakerArgsString(HandshakerArgs * args)42 std::string HandshakerArgsString(HandshakerArgs* args) {
43   size_t num_args = args->args != nullptr ? args->args->num_args : 0;
44   size_t read_buffer_length =
45       args->read_buffer != nullptr ? args->read_buffer->length : 0;
46   return absl::StrFormat(
47       "{endpoint=%p, args=%p {size=%" PRIuPTR
48       ": %s}, read_buffer=%p (length=%" PRIuPTR "), exit_early=%d}",
49       args->endpoint, args->args, num_args,
50       grpc_channel_args_string(args->args), args->read_buffer,
51       read_buffer_length, args->exit_early);
52 }
53 
54 }  // namespace
55 
HandshakeManager()56 HandshakeManager::HandshakeManager() {}
57 
58 /// Add \a mgr to the server side list of all pending handshake managers, the
59 /// list starts with \a *head.
60 // Not thread-safe. Caller needs to synchronize.
AddToPendingMgrList(HandshakeManager ** head)61 void HandshakeManager::AddToPendingMgrList(HandshakeManager** head) {
62   GPR_ASSERT(prev_ == nullptr);
63   GPR_ASSERT(next_ == nullptr);
64   next_ = *head;
65   if (*head) {
66     (*head)->prev_ = this;
67   }
68   *head = this;
69 }
70 
71 /// Remove \a mgr from the server side list of all pending handshake managers.
72 // Not thread-safe. Caller needs to synchronize.
RemoveFromPendingMgrList(HandshakeManager ** head)73 void HandshakeManager::RemoveFromPendingMgrList(HandshakeManager** head) {
74   if (next_ != nullptr) {
75     next_->prev_ = prev_;
76   }
77   if (prev_ != nullptr) {
78     prev_->next_ = next_;
79   } else {
80     GPR_ASSERT(*head == this);
81     *head = next_;
82   }
83 }
84 
85 /// Shutdown all pending handshake managers starting at head on the server
86 /// side. Not thread-safe. Caller needs to synchronize.
ShutdownAllPending(grpc_error * why)87 void HandshakeManager::ShutdownAllPending(grpc_error* why) {
88   auto* head = this;
89   while (head != nullptr) {
90     head->Shutdown(GRPC_ERROR_REF(why));
91     head = head->next_;
92   }
93   GRPC_ERROR_UNREF(why);
94 }
95 
Add(RefCountedPtr<Handshaker> handshaker)96 void HandshakeManager::Add(RefCountedPtr<Handshaker> handshaker) {
97   if (GRPC_TRACE_FLAG_ENABLED(grpc_handshaker_trace)) {
98     gpr_log(
99         GPR_INFO,
100         "handshake_manager %p: adding handshaker %s [%p] at index %" PRIuPTR,
101         this, handshaker->name(), handshaker.get(), handshakers_.size());
102   }
103   MutexLock lock(&mu_);
104   handshakers_.push_back(std::move(handshaker));
105 }
106 
~HandshakeManager()107 HandshakeManager::~HandshakeManager() { handshakers_.clear(); }
108 
Shutdown(grpc_error * why)109 void HandshakeManager::Shutdown(grpc_error* why) {
110   {
111     MutexLock lock(&mu_);
112     // Shutdown the handshaker that's currently in progress, if any.
113     if (!is_shutdown_ && index_ > 0) {
114       is_shutdown_ = true;
115       handshakers_[index_ - 1]->Shutdown(GRPC_ERROR_REF(why));
116     }
117   }
118   GRPC_ERROR_UNREF(why);
119 }
120 
121 // Helper function to call either the next handshaker or the
122 // on_handshake_done callback.
123 // Returns true if we've scheduled the on_handshake_done callback.
CallNextHandshakerLocked(grpc_error * error)124 bool HandshakeManager::CallNextHandshakerLocked(grpc_error* error) {
125   if (GRPC_TRACE_FLAG_ENABLED(grpc_handshaker_trace)) {
126     gpr_log(GPR_INFO,
127             "handshake_manager %p: error=%s shutdown=%d index=%" PRIuPTR
128             ", args=%s",
129             this, grpc_error_string(error), is_shutdown_, index_,
130             HandshakerArgsString(&args_).c_str());
131   }
132   GPR_ASSERT(index_ <= handshakers_.size());
133   // If we got an error or we've been shut down or we're exiting early or
134   // we've finished the last handshaker, invoke the on_handshake_done
135   // callback.  Otherwise, call the next handshaker.
136   if (error != GRPC_ERROR_NONE || is_shutdown_ || args_.exit_early ||
137       index_ == handshakers_.size()) {
138     if (error == GRPC_ERROR_NONE && is_shutdown_) {
139       error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("handshaker shutdown");
140       // It is possible that the endpoint has already been destroyed by
141       // a shutdown call while this callback was sitting on the ExecCtx
142       // with no error.
143       if (args_.endpoint != nullptr) {
144         // TODO(roth): It is currently necessary to shutdown endpoints
145         // before destroying then, even when we know that there are no
146         // pending read/write callbacks.  This should be fixed, at which
147         // point this can be removed.
148         grpc_endpoint_shutdown(args_.endpoint, GRPC_ERROR_REF(error));
149         grpc_endpoint_destroy(args_.endpoint);
150         args_.endpoint = nullptr;
151         grpc_channel_args_destroy(args_.args);
152         args_.args = nullptr;
153         grpc_slice_buffer_destroy_internal(args_.read_buffer);
154         gpr_free(args_.read_buffer);
155         args_.read_buffer = nullptr;
156       }
157     }
158     if (GRPC_TRACE_FLAG_ENABLED(grpc_handshaker_trace)) {
159       gpr_log(GPR_INFO,
160               "handshake_manager %p: handshaking complete -- scheduling "
161               "on_handshake_done with error=%s",
162               this, grpc_error_string(error));
163     }
164     // Cancel deadline timer, since we're invoking the on_handshake_done
165     // callback now.
166     grpc_timer_cancel(&deadline_timer_);
167     ExecCtx::Run(DEBUG_LOCATION, &on_handshake_done_, error);
168     is_shutdown_ = true;
169   } else {
170     auto handshaker = handshakers_[index_];
171     if (GRPC_TRACE_FLAG_ENABLED(grpc_handshaker_trace)) {
172       gpr_log(
173           GPR_INFO,
174           "handshake_manager %p: calling handshaker %s [%p] at index %" PRIuPTR,
175           this, handshaker->name(), handshaker.get(), index_);
176     }
177     handshaker->DoHandshake(acceptor_, &call_next_handshaker_, &args_);
178   }
179   ++index_;
180   return is_shutdown_;
181 }
182 
CallNextHandshakerFn(void * arg,grpc_error * error)183 void HandshakeManager::CallNextHandshakerFn(void* arg, grpc_error* error) {
184   auto* mgr = static_cast<HandshakeManager*>(arg);
185   bool done;
186   {
187     MutexLock lock(&mgr->mu_);
188     done = mgr->CallNextHandshakerLocked(GRPC_ERROR_REF(error));
189   }
190   // If we're invoked the final callback, we won't be coming back
191   // to this function, so we can release our reference to the
192   // handshake manager.
193   if (done) {
194     mgr->Unref();
195   }
196 }
197 
OnTimeoutFn(void * arg,grpc_error * error)198 void HandshakeManager::OnTimeoutFn(void* arg, grpc_error* error) {
199   auto* mgr = static_cast<HandshakeManager*>(arg);
200   if (error == GRPC_ERROR_NONE) {  // Timer fired, rather than being cancelled
201     mgr->Shutdown(GRPC_ERROR_CREATE_FROM_STATIC_STRING("Handshake timed out"));
202   }
203   mgr->Unref();
204 }
205 
DoHandshake(grpc_endpoint * endpoint,const grpc_channel_args * channel_args,grpc_millis deadline,grpc_tcp_server_acceptor * acceptor,grpc_iomgr_cb_func on_handshake_done,void * user_data)206 void HandshakeManager::DoHandshake(grpc_endpoint* endpoint,
207                                    const grpc_channel_args* channel_args,
208                                    grpc_millis deadline,
209                                    grpc_tcp_server_acceptor* acceptor,
210                                    grpc_iomgr_cb_func on_handshake_done,
211                                    void* user_data) {
212   bool done;
213   {
214     MutexLock lock(&mu_);
215     GPR_ASSERT(index_ == 0);
216     GPR_ASSERT(!is_shutdown_);
217     // Construct handshaker args.  These will be passed through all
218     // handshakers and eventually be freed by the on_handshake_done callback.
219     args_.endpoint = endpoint;
220     args_.args = grpc_channel_args_copy(channel_args);
221     args_.user_data = user_data;
222     args_.read_buffer =
223         static_cast<grpc_slice_buffer*>(gpr_malloc(sizeof(*args_.read_buffer)));
224     grpc_slice_buffer_init(args_.read_buffer);
225     if (acceptor != nullptr && acceptor->external_connection &&
226         acceptor->pending_data != nullptr) {
227       grpc_slice_buffer_swap(args_.read_buffer,
228                              &(acceptor->pending_data->data.raw.slice_buffer));
229     }
230     // Initialize state needed for calling handshakers.
231     acceptor_ = acceptor;
232     GRPC_CLOSURE_INIT(&call_next_handshaker_,
233                       &HandshakeManager::CallNextHandshakerFn, this,
234                       grpc_schedule_on_exec_ctx);
235     GRPC_CLOSURE_INIT(&on_handshake_done_, on_handshake_done, &args_,
236                       grpc_schedule_on_exec_ctx);
237     // Start deadline timer, which owns a ref.
238     Ref().release();
239     GRPC_CLOSURE_INIT(&on_timeout_, &HandshakeManager::OnTimeoutFn, this,
240                       grpc_schedule_on_exec_ctx);
241     grpc_timer_init(&deadline_timer_, deadline, &on_timeout_);
242     // Start first handshaker, which also owns a ref.
243     Ref().release();
244     done = CallNextHandshakerLocked(GRPC_ERROR_NONE);
245   }
246   if (done) {
247     Unref();
248   }
249 }
250 
251 }  // namespace grpc_core
252 
grpc_handshake_manager_add(grpc_handshake_manager * mgr,grpc_handshaker * handshaker)253 void grpc_handshake_manager_add(grpc_handshake_manager* mgr,
254                                 grpc_handshaker* handshaker) {
255   // This is a transition method to aid the API change for handshakers.
256   grpc_core::RefCountedPtr<grpc_core::Handshaker> refd_hs(
257       static_cast<grpc_core::Handshaker*>(handshaker));
258   mgr->Add(refd_hs);
259 }
260